Return-Path: Received: from mail-it1-f194.google.com ([209.85.166.194]:34964 "EHLO mail-it1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729439AbeJAVUb (ORCPT ); Mon, 1 Oct 2018 17:20:31 -0400 Received: by mail-it1-f194.google.com with SMTP id p64-v6so4680427itp.0 for ; Mon, 01 Oct 2018 07:42:22 -0700 (PDT) From: Trond Myklebust To: "J . Bruce Fields" Cc: linux-nfs@vger.kernel.org Subject: [PATCH 02/15] SUNRPC: Add lockless lookup of the server's auth domain Date: Mon, 1 Oct 2018 10:41:44 -0400 Message-Id: <20181001144157.3515-3-trond.myklebust@hammerspace.com> In-Reply-To: <20181001144157.3515-2-trond.myklebust@hammerspace.com> References: <20181001144157.3515-1-trond.myklebust@hammerspace.com> <20181001144157.3515-2-trond.myklebust@hammerspace.com> MIME-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org List-ID: Avoid taking the global auth_domain_lock in most lookups of the auth domain by adding an RCU protected lookup. Signed-off-by: Trond Myklebust --- include/linux/sunrpc/svcauth.h | 1 + net/sunrpc/auth_gss/svcauth_gss.c | 9 ++++++++- net/sunrpc/svcauth.c | 22 +++++++++++++++++++--- net/sunrpc/svcauth_unix.c | 10 ++++++++-- 4 files changed, 36 insertions(+), 6 deletions(-) diff --git a/include/linux/sunrpc/svcauth.h b/include/linux/sunrpc/svcauth.h index 04e404a07882..3e53a6e2ada7 100644 --- a/include/linux/sunrpc/svcauth.h +++ b/include/linux/sunrpc/svcauth.h @@ -82,6 +82,7 @@ struct auth_domain { struct hlist_node hash; char *name; struct auth_ops *flavour; + struct rcu_head rcu_head; }; /* diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c index 860f2a1bbb67..87c71fb0f0ea 100644 --- a/net/sunrpc/auth_gss/svcauth_gss.c +++ b/net/sunrpc/auth_gss/svcauth_gss.c @@ -1764,14 +1764,21 @@ svcauth_gss_release(struct svc_rqst *rqstp) } static void -svcauth_gss_domain_release(struct auth_domain *dom) +svcauth_gss_domain_release_rcu(struct rcu_head *head) { + struct auth_domain *dom = container_of(head, struct auth_domain, rcu_head); struct gss_domain *gd = container_of(dom, struct gss_domain, h); kfree(dom->name); kfree(gd); } +static void +svcauth_gss_domain_release(struct auth_domain *dom) +{ + call_rcu(&dom->rcu_head, svcauth_gss_domain_release_rcu); +} + static struct auth_ops svcauthops_gss = { .name = "rpcsec_gss", .owner = THIS_MODULE, diff --git a/net/sunrpc/svcauth.c b/net/sunrpc/svcauth.c index f83443856cd1..775b8c94265b 100644 --- a/net/sunrpc/svcauth.c +++ b/net/sunrpc/svcauth.c @@ -143,10 +143,11 @@ static struct hlist_head auth_domain_table[DN_HASHMAX]; static DEFINE_SPINLOCK(auth_domain_lock); static void auth_domain_release(struct kref *kref) + __releases(&auth_domain_lock) { struct auth_domain *dom = container_of(kref, struct auth_domain, ref); - hlist_del(&dom->hash); + hlist_del_rcu(&dom->hash); dom->flavour->domain_release(dom); spin_unlock(&auth_domain_lock); } @@ -175,7 +176,7 @@ auth_domain_lookup(char *name, struct auth_domain *new) } } if (new) - hlist_add_head(&new->hash, head); + hlist_add_head_rcu(&new->hash, head); spin_unlock(&auth_domain_lock); return new; } @@ -183,6 +184,21 @@ EXPORT_SYMBOL_GPL(auth_domain_lookup); struct auth_domain *auth_domain_find(char *name) { - return auth_domain_lookup(name, NULL); + struct auth_domain *hp; + struct hlist_head *head; + + head = &auth_domain_table[hash_str(name, DN_HASHBITS)]; + + rcu_read_lock(); + hlist_for_each_entry_rcu(hp, head, hash) { + if (strcmp(hp->name, name)==0) { + if (!kref_get_unless_zero(&hp->ref)) + hp = NULL; + rcu_read_unlock(); + return hp; + } + } + rcu_read_unlock(); + return NULL; } EXPORT_SYMBOL_GPL(auth_domain_find); diff --git a/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c index af7f28fb8102..84cf39021a03 100644 --- a/net/sunrpc/svcauth_unix.c +++ b/net/sunrpc/svcauth_unix.c @@ -37,20 +37,26 @@ struct unix_domain { extern struct auth_ops svcauth_null; extern struct auth_ops svcauth_unix; -static void svcauth_unix_domain_release(struct auth_domain *dom) +static void svcauth_unix_domain_release_rcu(struct rcu_head *head) { + struct auth_domain *dom = container_of(head, struct auth_domain, rcu_head); struct unix_domain *ud = container_of(dom, struct unix_domain, h); kfree(dom->name); kfree(ud); } +static void svcauth_unix_domain_release(struct auth_domain *dom) +{ + call_rcu(&dom->rcu_head, svcauth_unix_domain_release_rcu); +} + struct auth_domain *unix_domain_find(char *name) { struct auth_domain *rv; struct unix_domain *new = NULL; - rv = auth_domain_lookup(name, NULL); + rv = auth_domain_find(name); while(1) { if (rv) { if (new && rv != &new->h) -- 2.17.1